重庆石灰岩地区十大功劳(Mahonia fortunei)的光合响应研究

Studies About the Photosynthetic Response of the Shrub Mahonia fortunei in the Limestone Area of Chongqing

运用开放式气体交换CI 310便携式光合作用测定系统, 研究了重庆石灰岩地区适生灌木十大功劳(Mahoniafortunei)的光合光响应特性. 结果表明: 十大功劳的净光合速率对光合有效辐射的响应模型为二次曲线方程; 蒸腾速率对光的响应模型为一次线性方程; 气孔导度对光的响应趋势基本与光合速率一致; 胞间CO2 浓度的响应趋势与净光合速率恰好相反. 净光合速率、蒸腾速率、胞间CO2 浓度均与气孔导度有较强的线性关系. 十大功劳的光补偿点为61μmol·m-2·s-1, 光饱和点为1 725μmol·m-2·s-1, 为典型的阳性植物, 有较高的水分利用效率, 但以牺牲光能利用效率为代价. 这些光合响应特性是与石灰岩地区的生境相适应的.

To investigate how well leaf gas exchange of species responses to the different light environments , the authors use an open gas exchange system, CI-310 Portable Photosynthesis System to study the photosynthetic response of the shrub Mahonia fortunei in the limestone area of Chongqing. Photosynthetic rate (Pn), transpiration rate (E), intercellular CO 2 concentration (Ci), stomatal conducutance (Gs), water use efficiency (WUE) and light use efficiency (QUE) were examined under different photosynthetic radiation (PAR) intensities from 0 to 2 600 μmol·m^(-2)·s^(-1). Pn, E and Gs increased with enhanced PAR and Ci decreased with enhanced PAR. There were good linear relationships between Pn, E, Ci and Gs. Mahonia fortunei was a typical light-likely plant with the light compensation point 61 μmol·m^(-2)·s^(-1) and the light saturation point 1 725 μmol·m^(-2)·s^(-1). With high WUE and low QUE, Mahonia fortunei could adapt to the limestone habitat well.